Device and method of video encoding with first and second encoding code

1 . An image encoding device that encodes an image, the image encoding device comprising:

a processor; and

a non-transitory memory having stored thereon executable instructions, which cause the processor to:

generate a predictive image on a predictive unit for a current coding unit using predictive information, the prediction unit being included in the coding unit; and

wherein in a first mode, the processor generates a coefficient code string based on a residual coefficient, the residual coefficient being generated by performing an orthogonal transformation process and a quantizing process on a differential image between the image to be encoded and the generated predictive image,

wherein in a second mode, the processor directly uses the differential image to generate the coefficient code string without performing the orthogonal transformation process and the quantizing process, and

wherein a syntax of the current coding unit includes flag information indicating whether the first mode or the second mode is applied for the current coding unit and the syntax is included in a syntax of the coding unit separate from a syntax of the prediction unit included in the syntax of the coding unit, and

wherein in a second mode, the orthogonal transformation process and the quantizing process are bypassed.

2 . An image encoding method that encodes an image, the image encoding method comprising:

generating a predictive image on a predictive unit for a current coding unit using predictive information, the prediction unit being included in the coding unit; and

wherein in a first mode, generating a coefficient code string based on a residual coefficient, the residual coefficient being generated by performing an orthogonal transformation process and a quantizing process on a differential image between the image to be encoded and the generated predictive image,

wherein in a second mode, directly using the differential image to generate the coefficient code string without performing the orthogonal transformation process and the quantizing process, and

wherein a syntax of the current coding unit includes flag information indicating whether the first mode or the second mode is applied for the current coding unit and the syntax is included in a syntax of the coding unit separate from a syntax of the prediction unit included in the syntax of the coding unit, and

wherein in a second mode, the orthogonal transformation process and the quantizing process are bypassed.

3 . An image decoding device that decodes an encoded image, the image decoding device comprising:

a processor; and

a non-transitory memory having stored thereon executable instructions, which cause the processor to:

generate a predictive image on a predictive unit for a current coding unit using predictive information, the prediction unit being included in the coding unit; and

wherein in a first mode, the processor generates a residual coefficient based on a coefficient code string and performs an inverse quantizing process and an inverse orthogonal transformation process on the residual coefficient to output a residual decoded image, the residual decoded image is a differential image between the image to be decoded and the generated predictive image,

wherein in a second mode, the processor directly uses the coefficient code string to output the differential image without performing the inverse quantizing process and the orthogonal transformation process, and

wherein a syntax of the current coding unit includes flag information indicating whether the first mode or the second mode is applied for the current coding unit and the syntax is included in a syntax of the coding unit separate from a syntax of the prediction unit included in the syntax of the coding unit, and

wherein in a second mode, the orthogonal transformation process and the quantizing process are bypassed.

4 . An image decoding method that decodes an encoded image, the image decoding method comprising:

generating a predictive image on a predictive unit for a current coding unit using predictive information, the prediction unit being included in the coding unit; and

wherein in a first mode, generating a residual coefficient based on a coefficient code string and performing an inverse quantizing process and an inverse orthogonal transformation process on the residual coefficient to output a residual decoded image, the residual decoded image is a differential image between the image to be decoded and the generated predictive image,

wherein in a second mode, directly using the coefficient code string to output the differential image without performing the inverse quantizing process and the orthogonal transformation process, and

wherein a syntax of the current coding unit includes flag information indicating whether the first mode or the second mode is applied for the current coding unit and the syntax is included in a syntax of the coding unit separate from a syntax of the prediction unit included in the syntax of the coding unit, and

wherein in a second mode, the orthogonal transformation process and the quantizing process are bypassed.

5 . A non-transitory computer readable medium storing a bitstream, the bitstream including an encoded signal and syntax information according to which a decoder performs a method comprising:

generating a predictive image on a predictive unit for a current coding unit using predictive information, the prediction unit being included in the coding unit; and

wherein in a first mode, generating a residual coefficient based on a coefficient code string and performing an inverse quantizing process and an inverse orthogonal transformation process on the residual coefficient to output a residual decoded image, the residual decoded image is a differential image between the image to be decoded and the generated predictive image,

wherein in a second mode, directly using the coefficient code string to output the differential image without performing the inverse quantizing process and the orthogonal transformation process, and

wherein a syntax of the current coding unit includes flag information indicating whether the first mode or the second mode is applied for the current coding unit and the syntax is included in a syntax of the coding unit separate from a syntax of the prediction unit included in the syntax of the coding unit, and

wherein in a second mode, the orthogonal transformation process and the quantizing process are bypassed.